The present invention relates to an information-processing device in which a plurality of independent function devices is driven by a common power supply. More specifically, the present invention relates to a battery-operable information processing device and a method for controlling power consumption for the same.
Conventionally, power consumption control in battery-operable information processing devices such as notebook computers is performed using methods such as: (a) increasing efficiency of the power supply section or the battery; (b) reducing the power consumption of devices serving as function devices; (c) stopping or restricting operations of functions when they are not used. An extension of these methods involves keeping power cut off from functions such as modem functions in notebook computers that are used only under specific conditions.
In these conventional technologies, power conservation in the information processing devices is performed with the goal of providing the power required for operation of individual functions to the extent possible. In the conventional technologies described above, power is supplied equally to multiple function devices sharing a single power supply. Thus, no consideration is given to cases where there are different priorities in the multiple independently operable functions. For example, in an information processing device with an audio communication function (function device A) and a videophone function (function device B) sharing a power supply, the function device A would generally have a higher priority. However, with the power saving control system of the conventional technology, the continued use of the function device B will eventually reduce the battery capacity in the power supply to the point where the function device A will be inoperable. To prevent this, the user needs to explicitly stop using the function device B. In this example, the basis for priority is the function that needs to be used when a drop in battery capacity means only one of the functions can be used. In practice, priority levels are determined based on the power consumed by individual functions and the situation of individual users.